Connecting Storm-Relative Hodograph Characteristics to Vertical Variability of ZDR – KDP Separation

A repeated polarimetric radar signature in thunderstorms is the separation between enhanced regions of differential reflectivity (ZDR) and specific differential phase (KDP) due to hydrometeor size sorting. Past studies have utilized simple numerical models of hydrometeor size sorting to connect the enhanced regions of ZDR and KDP and the separation between them to aspects of the storm-relative winds taken over the entire sorting layer. These include relating the separation magnitude and orientation at the bottom of the sorting layer to the magnitude and orientation of the average storm-relative wind over the entire layer. Although using this polarimetric signature to gain insight into the average attributes of the storm-relative wind profile over the sorting layer, obtaining storm-relative wind estimates at several different vertical levels is highly desired. By comparing this signature, and therefore an average sense of the storm-relative wind, at different heights, an estimation of the storm-relative wind between those two heights can theoretically be obtained. Performing this process for several different height pairs could then provide an estimation of the storm-relative wind profile, or a radar-derived “pseudo-hodograph.” This methodology will be tested using output from a simple numerical size sorting model to assess the utility of analyzing the ZDR-KDP separation at several different heights to estimate a storm-relative wind profile. Preliminary results from idealized and observed/realistic wind profiles will be examined.